ADOEETINI. 277 



concave luasticiitiug surfaces. Into the curve the strong termimil 

 lobe of the mandible closely fits, and thus to all intents and 

 purposes both mouth and jaws are duplicated. The mandibles 

 meet at their inner basal part, where there is a very hard molar 

 or grinding surface. The maxilla (except in the degenerate 

 Heteroplithalmus) bears three, four or five short, but very strong, 

 finger-like teeth, radiating and more or less overlapping at their 

 outer edges, like the leaves of a fan, and one of the inner 

 teeth is generally broad and quadrate and appears as if separately 

 articulated at the base of the others. The palpus is either simple 

 and threadlike, or with the last joint short and conical. The 

 mentura varies very greatly in form, being correlated with the 

 labrum in its different phases, and generally notched or grooved 

 at the middle to receive the extremity of the latter ; but in 

 Schizadoretus its front margin is produced into two sharp points, 

 which are so prominent as to be visible from above. The antennae 

 are normally 10-jointed, but occasionally there are only nine joints, 

 and in Pseudadoretus there are ten in the males and nine in the 

 females. The front tibia is armed with three external teeth and 

 occasionally serrated above the teeth, the claws are long and very 

 unequal, and generally the longer one of the front and middle 

 feet is cleft at the tip. 



The outer edges of the elytra are not fringed with a thin mem- 

 brane, as in the Anoma.lini, but in some species of Adoretus 

 there is a smooth opaque epi[)leura of a different texture from the 

 remaining surface. The last abdominal spiracle is situated close 

 to the hinder margin of the penultimate dorsal segment, and in 

 some of the species the abdomen has a sharp keel along each side, 

 which may be continued obliquely across the corner of that segment 

 and so cut off the spiracle. 



The diffex'ences between the sexes are important and must be 

 carefully attended to if the accurate discrimination of the species 

 is to be attempted. The abdomen is convex in the female, and 

 straight or slightly concave in the male ; the last ventral segment 

 is large and more or less triangular in the former, and short and 

 transverse in the latter; and the pygidium is short and oblique in 

 the female, and larger and much more convex in the male. In 

 addition, the eyes are often much larger in the male than in the 

 female, the clypeus being then correspondingly reduced: the club 

 of the antenna is often longer; and where the longer front and 

 middle claws are cleft, the two divisions are approximately equal 

 in the female and very unequal in the male, the cleft being often 

 at a distance from the end and sometimes almost obliterated. In 

 Lissadoretus the claws are all undivided in the female, while in 

 the male they are of the normal type. 



The different genera have little to distinguish them super- 

 ficially, but there are great difterences in the structure of the 

 mouth, and therefore in the manner of feeding. 



The predominant genus, Adoi'etus, is the only one of whose 

 habits anything is known. It consists of a very large number 



